Help... Newbie Installing a shower below-grade

Hey, I just got a house, and in the basement they put a shower in over just a old floor drain, its a 6.5inch hole... all they did was tile around the drain, They left the old nasty metal grate over the drain,, anyways I took all the tile up, now my question is how do I install a real shower drain to the old drain.. i want to just Rock the walls and floor and tile them,,, thanks for the help.....